A chip with many functions, such as a memory device and a system LSI (large scale integration) device, includes circuits whose initial conditions are to be set for proper operations. For example, an initializing operation is required to be performed before a chip operates normally. In general, an initializing operation is performed in response to a power-on reset signal being output from a power-on reset circuit.
A power-on reset circuit generates a power-on reset signal when a ground voltage of a chip increases to a predetermined voltage level. By using the power-on reset signal in the chip, regions requiring initialization, such as latches, flip-flops and registers, may be reset before the chip operates normally. However, some power-on reset circuits are not sufficiently electrically stable or resistant to electrical noise, consume too much power or are significantly affected by environmental parameters such as temperature or physical parameters such as process variations.